Theoretical Foundations
Understanding Newton's First Law (Law of Inertia)
1. The Principle
An object preserves its velocity (speed and direction) unless a non-zero external net force acts on it. Rest is simply a constant velocity of zero.
2. Mathematical Model
Newtonian mechanics represents this with:
ΣF = 0 ⇔ a = 0
If net force is zero, acceleration is zero, maintaining a perfectly straight and constant velocity curve over time.
3. What is Inertia?
Inertia is the natural tendency of matter to resist shifts in motion. Mass is the numeric, scalar metric of an object's inertia.